std::ios_base::Init

From Cppreference

C++ Standard Library
Language Utilities library Strings library Containers library Algorithms library Iterators library Numerics library Input/output library Localizations library Regular expressions library (C++11) Atomic operations library (C++11) Thread support library (C++11)
Input/output library
basic_streambuf basic_filebuf basic_stringbuf ios_base basic_ios basic_istream basic_ostream basic_iostream basic_ifstream basic_ofstream basic_fstream basic_istringstream basic_ostringstream basic_stringstream I/O manipulators C-style I/O
std::ios_base
Member functions ios_base::ios_base ios_base::~ios_base Formatting ios_base::flags ios_base::setf ios_base::unsetf ios_base::precision ios_base::width Locales ios_base::imbue ios_base::getloc Internal extensible array ios_base::xalloc ios_base::iword ios_base::pword Miscellaneous ios_base::register_callback ios_base::sync_with_stdio Member classes ios_base::failure ios_base::Init Member types ios_base::openmode ios_base::fmtflags ios_base::iostate ios_base::seekdir ios_base::event ios_base::event_callback

class Init;

This class is used to ensure that the default C++ streams (std::cin, std::cout, etc.) are properly initialized and destructed. The class tracks how many instances of it are created and initializes the C++ streams when the first instance is constructed as well as flushes the output streams when the last instance is destructed.

[edit] Member functions

(constructor)	if *this is the first instance created, initializes the default C++ streams (public member function)
(destructor)	if *this is the last instance created, flushes the default C++ streams (public member function)